Does anyone still use them?
Yes. Unlike phones, they are dedicated devices and do one thing only, usually better. For example, they are not interrupted by phone calls - which could be a real issue if you're navigating in some complex area., and have no background processes that could slow down processing.
I also like small phones, but use a GPS device with a far larger screen. When they are properly car-integrated, they can also get more data - i.e. the car speed when the GPS signal is not good enough, and also can use an external antenna for better reception.
You may also have maps for many countries, and won't need a data connection when abroad. Now most offer "lifetime" maps, if you drive quite often to new destinations, a dedicated GPS is usually better than a phone.